Poor sleep and fatigue are commonly encountered in the practice of nephrology. In the general population, sleep studies using polysomnography show a substantial prevalence of sleep disordered breathing and other causes of sleep fragmentation in healthy adults that clearly contribute to sleepiness and fatigue, hypertension and cardiovascular disease. Potentially, such disorder could contribute to the very high rates of morbidity and mortality in the chronic kidney disease population. The general hypothesis for the proposed research program is that kidney failure is related to sleep disorders and these sleep disorders impact on daytime functioning. The Principal Investigator has designed a rigorous training program that will provide him with the necessary research skills, hands-on mentoring experiences, and content area expertise to develop into an independent investigator in the field of sleep and daytime functioning in chronic kidney disease. He will take courses designed to provide him the statistical, study design, and measurement methodology to carry out original research. His sponsors have extensive experience in clinical epidemiology, dialysis outcomes research, sleep disorders epidemiology and functioning outcomes methodology and are committed to his career development. The few preliminary studies using polysomnography suggest that sleep disorders may affect the majority in dialysis patients. The proposed study is designed to evaluate the full spectrum of both objectively assessed and self-reported sleep disorders and evaluate daytime functioning before and after kidney transplantation. The Specific Aims are 1) To characterize sleep and daytime functioning in persons with advanced kidney disease and on hemodialysis 2) To characterize changes in sleep and daytime functioning in persons after kidney transplantation. Statistical power demonstrates that the proposed study has an adequate sample size to assess each aim and a pilot project has demonstrated the feasibility of recruiting patients with chronic kidney disease for sleep and daytime functioning assessments. The team of experienced mentors and consulting scientists will monitor his progress in completing his project and his career development. The proposed training program and research projects will serve as a foundation for future projects to improve the sleep and daytime functioning in persons with chronic kidney disease.